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Merge branch 'stable/128gb.v5.1' into stable/for-linus-3.7
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* stable/128gb.v5.1:
  xen/mmu: If the revector fails, don't attempt to revector anything else.
  xen/p2m: When revectoring deal with holes in the P2M array.
  xen/mmu: Release just the MFN list, not MFN list and part of pagetables.
  xen/mmu: Remove from __ka space PMD entries for pagetables.
  xen/mmu: Copy and revector the P2M tree.
  xen/p2m: Add logic to revector a P2M tree to use __va leafs.
  xen/mmu: Recycle the Xen provided L4, L3, and L2 pages
  xen/mmu: For 64-bit do not call xen_map_identity_early
  xen/mmu: use copy_page instead of memcpy.
  xen/mmu: Provide comments describing the _ka and _va aliasing issue
  xen/mmu: The xen_setup_kernel_pagetable doesn't need to return anything.
  Revert "xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain." and "xen/x86: Use memblock_reserve for sensitive areas."
  xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain.
  xen/x86: Use memblock_reserve for sensitive areas.
  xen/p2m: Fix the comment describing the P2M tree.

Conflicts:
	arch/x86/xen/mmu.c

The pagetable_init is the old xen_pagetable_setup_done and xen_pagetable_setup_start
rolled in one.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Konrad Rzeszutek Wilk committed Sep 12, 2012
2 parents 25a765b + 3287318 commit 98104c3
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Showing 5 changed files with 254 additions and 47 deletions.
5 changes: 1 addition & 4 deletions arch/x86/xen/enlighten.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1290,7 +1290,6 @@ asmlinkage void __init xen_start_kernel(void)
{
struct physdev_set_iopl set_iopl;
int rc;
pgd_t *pgd;

if (!xen_start_info)
return;
Expand Down Expand Up @@ -1382,8 +1381,6 @@ asmlinkage void __init xen_start_kernel(void)
acpi_numa = -1;
#endif

pgd = (pgd_t *)xen_start_info->pt_base;

/* Don't do the full vcpu_info placement stuff until we have a
possible map and a non-dummy shared_info. */
per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
Expand All @@ -1392,7 +1389,7 @@ asmlinkage void __init xen_start_kernel(void)
early_boot_irqs_disabled = true;

xen_raw_console_write("mapping kernel into physical memory\n");
pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages);

/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();
Expand Down
183 changes: 148 additions & 35 deletions arch/x86/xen/mmu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -84,14 +84,15 @@
*/
DEFINE_SPINLOCK(xen_reservation_lock);

#ifdef CONFIG_X86_32
/*
* Identity map, in addition to plain kernel map. This needs to be
* large enough to allocate page table pages to allocate the rest.
* Each page can map 2MB.
*/
#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);

#endif
#ifdef CONFIG_X86_64
/* l3 pud for userspace vsyscall mapping */
static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
Expand Down Expand Up @@ -1176,13 +1177,6 @@ static void xen_exit_mmap(struct mm_struct *mm)

static void xen_post_allocator_init(void);

static void __init xen_pagetable_init(void)
{
paging_init();
xen_setup_shared_info();
xen_post_allocator_init();
}

static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
{
/* reserve the range used */
Expand All @@ -1197,6 +1191,87 @@ static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
}
}

#ifdef CONFIG_X86_64
static void __init xen_cleanhighmap(unsigned long vaddr,
unsigned long vaddr_end)
{
unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);

/* NOTE: The loop is more greedy than the cleanup_highmap variant.
* We include the PMD passed in on _both_ boundaries. */
for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
pmd++, vaddr += PMD_SIZE) {
if (pmd_none(*pmd))
continue;
if (vaddr < (unsigned long) _text || vaddr > kernel_end)
set_pmd(pmd, __pmd(0));
}
/* In case we did something silly, we should crash in this function
* instead of somewhere later and be confusing. */
xen_mc_flush();
}
#endif
static void __init xen_pagetable_init(void)
{
#ifdef CONFIG_X86_64
unsigned long size;
unsigned long addr;
#endif
paging_init();
xen_setup_shared_info();
#ifdef CONFIG_X86_64
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
unsigned long new_mfn_list;

size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));

/* On 32-bit, we get zero so this never gets executed. */
new_mfn_list = xen_revector_p2m_tree();
if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
/* using __ka address and sticking INVALID_P2M_ENTRY! */
memset((void *)xen_start_info->mfn_list, 0xff, size);

/* We should be in __ka space. */
BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
addr = xen_start_info->mfn_list;
/* We roundup to the PMD, which means that if anybody at this stage is
* using the __ka address of xen_start_info or xen_start_info->shared_info
* they are in going to crash. Fortunatly we have already revectored
* in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
size = roundup(size, PMD_SIZE);
xen_cleanhighmap(addr, addr + size);

size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
memblock_free(__pa(xen_start_info->mfn_list), size);
/* And revector! Bye bye old array */
xen_start_info->mfn_list = new_mfn_list;
} else
goto skip;
}
/* At this stage, cleanup_highmap has already cleaned __ka space
* from _brk_limit way up to the max_pfn_mapped (which is the end of
* the ramdisk). We continue on, erasing PMD entries that point to page
* tables - do note that they are accessible at this stage via __va.
* For good measure we also round up to the PMD - which means that if
* anybody is using __ka address to the initial boot-stack - and try
* to use it - they are going to crash. The xen_start_info has been
* taken care of already in xen_setup_kernel_pagetable. */
addr = xen_start_info->pt_base;
size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);

xen_cleanhighmap(addr, addr + size);
xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
#ifdef DEBUG
/* This is superflous and is not neccessary, but you know what
* lets do it. The MODULES_VADDR -> MODULES_END should be clear of
* anything at this stage. */
xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
#endif
skip:
#endif
xen_post_allocator_init();
}
static void xen_write_cr2(unsigned long cr2)
{
this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
Expand Down Expand Up @@ -1652,7 +1727,7 @@ static void set_page_prot(void *addr, pgprot_t prot)
if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
BUG();
}

#ifdef CONFIG_X86_32
static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
{
unsigned pmdidx, pteidx;
Expand Down Expand Up @@ -1703,7 +1778,7 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)

set_page_prot(pmd, PAGE_KERNEL_RO);
}

#endif
void __init xen_setup_machphys_mapping(void)
{
struct xen_machphys_mapping mapping;
Expand Down Expand Up @@ -1731,7 +1806,20 @@ static void convert_pfn_mfn(void *v)
for (i = 0; i < PTRS_PER_PTE; i++)
pte[i] = xen_make_pte(pte[i].pte);
}

static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
unsigned long addr)
{
if (*pt_base == PFN_DOWN(__pa(addr))) {
set_page_prot((void *)addr, PAGE_KERNEL);
clear_page((void *)addr);
(*pt_base)++;
}
if (*pt_end == PFN_DOWN(__pa(addr))) {
set_page_prot((void *)addr, PAGE_KERNEL);
clear_page((void *)addr);
(*pt_end)--;
}
}
/*
* Set up the initial kernel pagetable.
*
Expand All @@ -1743,44 +1831,67 @@ static void convert_pfn_mfn(void *v)
* of the physical mapping once some sort of allocator has been set
* up.
*/
pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
unsigned long max_pfn)
void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pud_t *l3;
pmd_t *l2;
unsigned long addr[3];
unsigned long pt_base, pt_end;
unsigned i;

/* max_pfn_mapped is the last pfn mapped in the initial memory
* mappings. Considering that on Xen after the kernel mappings we
* have the mappings of some pages that don't exist in pfn space, we
* set max_pfn_mapped to the last real pfn mapped. */
max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));

pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
pt_end = pt_base + xen_start_info->nr_pt_frames;

/* Zap identity mapping */
init_level4_pgt[0] = __pgd(0);

/* Pre-constructed entries are in pfn, so convert to mfn */
/* L4[272] -> level3_ident_pgt
* L4[511] -> level3_kernel_pgt */
convert_pfn_mfn(init_level4_pgt);

/* L3_i[0] -> level2_ident_pgt */
convert_pfn_mfn(level3_ident_pgt);
/* L3_k[510] -> level2_kernel_pgt
* L3_i[511] -> level2_fixmap_pgt */
convert_pfn_mfn(level3_kernel_pgt);

/* We get [511][511] and have Xen's version of level2_kernel_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);

memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

addr[0] = (unsigned long)pgd;
addr[1] = (unsigned long)l3;
addr[2] = (unsigned long)l2;
/* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
* Both L4[272][0] and L4[511][511] have entries that point to the same
* L2 (PMD) tables. Meaning that if you modify it in __va space
* it will be also modified in the __ka space! (But if you just
* modify the PMD table to point to other PTE's or none, then you
* are OK - which is what cleanup_highmap does) */
copy_page(level2_ident_pgt, l2);
/* Graft it onto L4[511][511] */
copy_page(level2_kernel_pgt, l2);

/* Get [511][510] and graft that in level2_fixmap_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

/* Set up identity map */
xen_map_identity_early(level2_ident_pgt, max_pfn);
copy_page(level2_fixmap_pgt, l2);
/* Note that we don't do anything with level1_fixmap_pgt which
* we don't need. */

/* Make pagetable pieces RO */
set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);

Expand All @@ -1791,22 +1902,28 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
/* Unpin Xen-provided one */
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

/* Switch over */
pgd = init_level4_pgt;

/*
* At this stage there can be no user pgd, and no page
* structure to attach it to, so make sure we just set kernel
* pgd.
*/
xen_mc_batch();
__xen_write_cr3(true, __pa(pgd));
__xen_write_cr3(true, __pa(init_level4_pgt));
xen_mc_issue(PARAVIRT_LAZY_CPU);

memblock_reserve(__pa(xen_start_info->pt_base),
xen_start_info->nr_pt_frames * PAGE_SIZE);
/* We can't that easily rip out L3 and L2, as the Xen pagetables are
* set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
* the initial domain. For guests using the toolstack, they are in:
* [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
* rip out the [L4] (pgd), but for guests we shave off three pages.
*/
for (i = 0; i < ARRAY_SIZE(addr); i++)
check_pt_base(&pt_base, &pt_end, addr[i]);

return pgd;
/* Our (by three pages) smaller Xen pagetable that we are using */
memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
/* Revector the xen_start_info */
xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
}
#else /* !CONFIG_X86_64 */
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
Expand All @@ -1831,8 +1948,7 @@ static void __init xen_write_cr3_init(unsigned long cr3)
*/
swapper_kernel_pmd =
extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
memcpy(swapper_kernel_pmd, initial_kernel_pmd,
sizeof(pmd_t) * PTRS_PER_PMD);
copy_page(swapper_kernel_pmd, initial_kernel_pmd);
swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
Expand All @@ -1849,8 +1965,7 @@ static void __init xen_write_cr3_init(unsigned long cr3)
pv_mmu_ops.write_cr3 = &xen_write_cr3;
}

pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
unsigned long max_pfn)
void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pmd_t *kernel_pmd;

Expand All @@ -1862,11 +1977,11 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
512*1024);

kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
copy_page(initial_kernel_pmd, kernel_pmd);

xen_map_identity_early(initial_kernel_pmd, max_pfn);

memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
copy_page(initial_page_table, pgd);
initial_page_table[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);

Expand All @@ -1882,8 +1997,6 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,

memblock_reserve(__pa(xen_start_info->pt_base),
xen_start_info->nr_pt_frames * PAGE_SIZE);

return initial_page_table;
}
#endif /* CONFIG_X86_64 */

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